Solving the DragTarget Data Issue in Flutter скачать в хорошем качестве

Solving the DragTarget Data Issue in Flutter

Learn how to fix the issue with `DragTarget` showing wrong data when hovering with a new `Draggable` in Flutter. This guide breaks down the solution into easy-to-follow steps. --- This video is based on the question https://stackoverflow.com/q/66034914/ asked by the user 'soulcoding' ( https://stackoverflow.com/u/15139836/ ) and on the answer https://stackoverflow.com/a/66238568/ provided by the user 'soulcoding' ( https://stackoverflow.com/u/15139836/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Flutter: DragTarget shows wrong data when hovering over it with a new Draggable Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l... The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- Solving the DragTarget Data Issue in Flutter: A Comprehensive Guide If you're diving into Flutter and working on drag and drop functionality, you might find yourself facing some challenges when implementing Draggable and DragTarget widgets. One common issue developers encounter, especially beginners, is when the DragTarget displays the wrong data during hover states. In this guide, we will explore this problem and provide a detailed solution that will not only resolve the issue but also enhance your understanding of state management in Flutter. Understanding the Problem As described by a novice Flutter developer, the task at hand involves creating an interactive periodic table where elements can be dragged and dropped onto specific targets. The challenge arises when trying to show information related to the dropped element on the DragTarget. While it works for empty targets, hovering over targets that already contain data incorrectly changes the displayed information to that of the last dragged item. Key Issues Identified: Improper Data Binding: The DragTarget does not maintain a unique reference to each specific element. Instead, it appears to share the data with the last element that was dragged. State Management Confusion: Difficulty in handling states for multiple draggable items and ensuring that they do not interfere with each other when dropped or hovered. Crafting the Solution To tackle the issue effectively, we need to ensure that our DragTarget correctly references and binds to its specific element data. Here's a structured breakdown of how to achieve this. 1. Using a Model Class By implementing a model class for our elements, we can create deep copies of the data and bind them correctly. This helps to ensure that each DragTarget refers to its individual piece of data rather than shared data across different targets. ElementModel Class Here's how you can define an ElementModel class: [[See Video to Reveal this Text or Code Snippet]] 2. Deep Copying the Data In the getElements() function, create deep copies of your elementData. Instead of manipulating the original structure, we leverage our model to maintain the uniqueness of each DragTarget. [[See Video to Reveal this Text or Code Snippet]] 3. Modifying DragTarget Behavior When implementing the DragTarget, utilize the data from the deep copies. The changes you make upon accepting data should refer to the unique instance of each target. [[See Video to Reveal this Text or Code Snippet]] 4. Testing Your Implementation After modifying your code, ensure that you conduct thorough testing. Drag different elements to various DragTargets, observe the hover states, and confirm that the correct data is displayed for each target. Conclusion By implementing a dedicated model for your elements and ensuring that each DragTarget maintains a distinct copy of its data, you can effectively resolve the issue of incorrect data display when hovering over these targets. This enhanced structure will not only fix the current problem but will also serve as a solid foundation for future enhancements to your drag and drop functionalities in Flutter. Are you ready to try out these solutions in your Flutter application? Keep exploring and happy coding!